US5773900A - Device for suppressing signal interference - Google Patents

Device for suppressing signal interference Download PDF

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Publication number
US5773900A
US5773900A US08/793,285 US79328597A US5773900A US 5773900 A US5773900 A US 5773900A US 79328597 A US79328597 A US 79328597A US 5773900 A US5773900 A US 5773900A
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Prior art keywords
input lines
microcomputer
measurement interval
electronic device
coupled
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US08/793,285
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Hartmut Schumacher
Klaus Oswald
Norbert Crispin
Martin Daiber
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Robert Bosch GmbH
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Robert Bosch GmbH
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Assigned to ROBERT BOSCH GMBH reassignment ROBERT BOSCH GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CRISPIN, NORBERT, DAIBER, MARTIN, OSWALD, KLAUS, SCHUMACHER, HARTMUT
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/028—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/09—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by piezoelectric pick-up
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/05—Digital input using the sampling of an analogue quantity at regular intervals of time, input from a/d converter or output to d/a converter

Definitions

  • the present invention relates to an electronic device.
  • a conventional electronic device is described in U.S. Pat. No. 5,037,129. If sensor signals that are affected by severe interfering signals must be processed in such a conventional device, undesired interference can occur, particularly during a conversion of the analog sensor signals into digital signals. These interferences are perceptible as, for example, "crosstalk," the coupling-in of undesired interfering signal components on adjacent lines or, for example, adjacent channels of a multi-channel analog/digital converter (A/D converter).
  • crosstalk the coupling-in of undesired interfering signal components on adjacent lines or, for example, adjacent channels of a multi-channel analog/digital converter (A/D converter).
  • the electronic device of the present invention allows particularly simple and elegant suppression of undesired interfering pulses, so the output signal of a sensor to be processed as a desired measured signal is essentially further processed free from interference; in particular, it can be converted into a corresponding digital output signal.
  • FIG. 1 shows a block diagram of the electronic device according to the present invention.
  • FIG. 2a shows a plot of an output signal of a sensor as a function of time for the electronic device shown in FIG. 1.
  • FIG. 2b shows a plot of a resistance as a function of time for the electronic device shown in FIG. 1.
  • FIG. 1 An electronic device for controlling protective devices (e.g., an airbag system) for vehicle passengers, is shown, for example, as a block diagram in FIG. 1.
  • the device includes an acceleration-sensitive sensor 1, preferably a piezoelectric sensor whose output connection is connected to a voltage divider R1, R2.
  • the low end of voltage divider R1, R2 is connected to the ground connection.
  • the tap of voltage divider R1, R2 is connected to an input connection 0 of a microcomputer 2 that includes a plurality of input connections.
  • the plurality of input connections 0 through 7 of microcomputer 2 are connected in time-multiplex fashion to the input connection of an A/D converter 30 contained in the microcomputer, which converts the analog output signals of sensor 1 into corresponding digital signals.
  • Each of the illustrated input connections 0 through 7 can be switched with a corresponding input wiring, such as input connection 0. Consequently, a plurality of sensors 1 and a plurality of voltage dividers R1, R2 can be provided which are connected to corresponding input connections of microcomputer 2.
  • Microcomputer 2 further comprises two reference-voltage connections 20, 21, to which reference voltages can be applied.
  • reference-voltage connection 20 can be connected to the ground connection, while a predeterminable reference voltage can be applied to reference-voltage connection 21.
  • An output connection 22 of microcomputer 2 is connected with at least one airbag system 3 provided for passenger protection. The output signal present at output connection 10 of sensor 1 is supplied to voltage divider R1, R2 and scaled to the detection range of the A/D converter of microcomputer 2.
  • This detection range is, for example, in the voltage interval between 0 and 5 Volts.
  • the actual measuring task involved in detecting the output signal of sensor 1 is fulfilled. If, however, interfering voltages occur which are superimposed over the output signal of sensor 1 and are outside of the admissible measuring interval, protective circuits in the input wiring of the A/D converter must bear this additional stress. Usually, this is possible in currently commercially-available microcomputers without resulting in the destruction of the input wiring.
  • the response of the input wiring of an A/D channel for example the channel indicated by 0 in FIG. 1, which is provided for purposes of protection, cannot guarantee that measurements can be taken on the other channels, for example channels 1 through 7, without interference.
  • the input connection of the microcomputer that respectively leads to the A/D converter is configured such that it can be connected to two different potential values.
  • the assumption here is that the output signals of sensors 1 are respectively scanned in time-multiplex or cyclical fashion so that the output signals detected during the scan time can be converted into digital signals.
  • the operating time can thus be divided into measurement phases and inactive phases.
  • the respective input connection of microcomputer 2 is connected to a first potential, and during the respective inactive phases it is connected to a potential that is different from the first.
  • An input connection of a microcomputer is connected, particularly simply and practically, to a respectively different potential in that it is connected to a digital port of microcomputer 2.
  • input connection 0 of microcomputer 2 is additionally connected to the digital port DO of microcomputer 2.
  • the A/D inputs 0 through 7 of microcomputer 2 are connected in time-multiplex fashion to the input connection of the A/D converter disposed in microcomputer 2 such that each input channel 0 through 7 is connected to the input connection of the A/D converter for a predeterminable measurement time, for example 6 microseconds. This measuring process is explained in conjunction with the plots shown in FIGS. 2a and 2b.
  • FIG. 1 An input connection of a microcomputer is connected, particularly simply and practically, to a respectively different potential in that it is connected to a digital port of microcomputer 2.
  • input connection 0 of microcomputer 2 is additionally connected to the digital port DO of microcomputer 2.
  • the A/D inputs 0 through 7 of microcomputer 2 are connected in time-multiplex fashion to the input connection of the A/D converter
  • FIG. 2a shows, as an example, the output signal of sensor 1, namely the voltage U MESS1 , as a function of the time t.
  • This output signal reaches A/D input 0 of microcomputer 2 via voltage divider R1, R2, and is scanned and converted into a corresponding digital signal during a time interval T1, T2.
  • digital port DO of microcomputer 2 that is connected to A/D output 0 during this time interval T1, T2 is actuated such that it is in the tri-state, that is, a high-resistance state.
  • it represents a resistance R1, which is significantly greater than the resistance R0 assumed by digital port D0 of microcomputer 2 outside of time interval T1, T2. Because of the relatively low-resistance connection of A/D input 0 outside of time interval T1, T2, interfering pulses superimposed over the output signal of sensor 1 cannot lead to crosstalk and interference of the measurements at the other A/D inputs.
  • resistances R1, R2 of voltage divider R1, R2 each have a value of, for example, 50 K ⁇ . It is further assumed that an interfering voltage of ⁇ 50 Volts is superimposed over the output signal U MESS1 of sensor 1. Outside of time interval T1, T2, digital port DO of microcomputer 2 is connected to a relatively low resistance R0 of, for example, 100 Ohms. Consequently, a maximum interfering voltage of less than 100 mV, which can no longer cause interference, is still present at A/D input 0 of microcomputer 2.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Analogue/Digital Conversion (AREA)
  • Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
  • Air Bags (AREA)

Abstract

A device for suppressing interference signals for a microprocessor evaluating a plurality of sensor signals on respective input lines coupled thereto. Each of the input lines is selectively coupled to a first resistance during a measurement interval and selectively coupled to a second resistance during an interval outside of the measurement interval.

Description

FIELD OF THE INVENTION
The present invention relates to an electronic device.
BACKGROUND INFORMATION
A conventional electronic device is described in U.S. Pat. No. 5,037,129. If sensor signals that are affected by severe interfering signals must be processed in such a conventional device, undesired interference can occur, particularly during a conversion of the analog sensor signals into digital signals. These interferences are perceptible as, for example, "crosstalk," the coupling-in of undesired interfering signal components on adjacent lines or, for example, adjacent channels of a multi-channel analog/digital converter (A/D converter).
SUMMARY OF THE INVENTION
The electronic device of the present invention allows particularly simple and elegant suppression of undesired interfering pulses, so the output signal of a sensor to be processed as a desired measured signal is essentially further processed free from interference; in particular, it can be converted into a corresponding digital output signal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of the electronic device according to the present invention.
FIG. 2a shows a plot of an output signal of a sensor as a function of time for the electronic device shown in FIG. 1.
FIG. 2b shows a plot of a resistance as a function of time for the electronic device shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
An electronic device for controlling protective devices (e.g., an airbag system) for vehicle passengers, is shown, for example, as a block diagram in FIG. 1. The device includes an acceleration-sensitive sensor 1, preferably a piezoelectric sensor whose output connection is connected to a voltage divider R1, R2. The low end of voltage divider R1, R2 is connected to the ground connection. In the block diagram shown, the tap of voltage divider R1, R2 is connected to an input connection 0 of a microcomputer 2 that includes a plurality of input connections. The plurality of input connections 0 through 7 of microcomputer 2 are connected in time-multiplex fashion to the input connection of an A/D converter 30 contained in the microcomputer, which converts the analog output signals of sensor 1 into corresponding digital signals. Each of the illustrated input connections 0 through 7 can be switched with a corresponding input wiring, such as input connection 0. Consequently, a plurality of sensors 1 and a plurality of voltage dividers R1, R2 can be provided which are connected to corresponding input connections of microcomputer 2. Microcomputer 2 further comprises two reference- voltage connections 20, 21, to which reference voltages can be applied. As an example, reference-voltage connection 20 can be connected to the ground connection, while a predeterminable reference voltage can be applied to reference-voltage connection 21. An output connection 22 of microcomputer 2 is connected with at least one airbag system 3 provided for passenger protection. The output signal present at output connection 10 of sensor 1 is supplied to voltage divider R1, R2 and scaled to the detection range of the A/D converter of microcomputer 2. This detection range is, for example, in the voltage interval between 0 and 5 Volts. Thus, the actual measuring task involved in detecting the output signal of sensor 1 is fulfilled. If, however, interfering voltages occur which are superimposed over the output signal of sensor 1 and are outside of the admissible measuring interval, protective circuits in the input wiring of the A/D converter must bear this additional stress. Usually, this is possible in currently commercially-available microcomputers without resulting in the destruction of the input wiring. However, in most cases the response of the input wiring of an A/D channel, for example the channel indicated by 0 in FIG. 1, which is provided for purposes of protection, cannot guarantee that measurements can be taken on the other channels, for example channels 1 through 7, without interference. To assure extensive suppression of interference even in this situation, the input connection of the microcomputer that respectively leads to the A/D converter is configured such that it can be connected to two different potential values. The assumption here is that the output signals of sensors 1 are respectively scanned in time-multiplex or cyclical fashion so that the output signals detected during the scan time can be converted into digital signals. The operating time can thus be divided into measurement phases and inactive phases. According to the present invention, it is provided that, during the respective measuring phases, the respective input connection of microcomputer 2 is connected to a first potential, and during the respective inactive phases it is connected to a potential that is different from the first. Thus, it is ensured that interfering pulses that occur at an input connection of microcomputer 2 during an inactive phase cannot interfere with adjacent signal channels. An input connection of a microcomputer is connected, particularly simply and practically, to a respectively different potential in that it is connected to a digital port of microcomputer 2. As shown in FIG. 1, for example, input connection 0 of microcomputer 2 is additionally connected to the digital port DO of microcomputer 2. The A/D inputs 0 through 7 of microcomputer 2 are connected in time-multiplex fashion to the input connection of the A/D converter disposed in microcomputer 2 such that each input channel 0 through 7 is connected to the input connection of the A/D converter for a predeterminable measurement time, for example 6 microseconds. This measuring process is explained in conjunction with the plots shown in FIGS. 2a and 2b. FIG. 2a shows, as an example, the output signal of sensor 1, namely the voltage UMESS1, as a function of the time t. This output signal reaches A/D input 0 of microcomputer 2 via voltage divider R1, R2, and is scanned and converted into a corresponding digital signal during a time interval T1, T2. As can be inferred from FIG. 2b, digital port DO of microcomputer 2 that is connected to A/D output 0 during this time interval T1, T2 is actuated such that it is in the tri-state, that is, a high-resistance state. For example, it represents a resistance R1, which is significantly greater than the resistance R0 assumed by digital port D0 of microcomputer 2 outside of time interval T1, T2. Because of the relatively low-resistance connection of A/D input 0 outside of time interval T1, T2, interfering pulses superimposed over the output signal of sensor 1 cannot lead to crosstalk and interference of the measurements at the other A/D inputs.
In one embodiment of the present invention, resistances R1, R2 of voltage divider R1, R2 each have a value of, for example, 50 KΩ. It is further assumed that an interfering voltage of ±50 Volts is superimposed over the output signal UMESS1 of sensor 1. Outside of time interval T1, T2, digital port DO of microcomputer 2 is connected to a relatively low resistance R0 of, for example, 100 Ohms. Consequently, a maximum interfering voltage of less than 100 mV, which can no longer cause interference, is still present at A/D input 0 of microcomputer 2.

Claims (4)

What is claimed is:
1. An electronic device comprising:
a sensor generating a first analog output signal on a sensor output line; and
a microcomputer including a p lurality of A/D input lines, the sensor output line coupled to a first one of the plurality of A/D input lines, the microcomputer evaluating the first analog output signal and evaluating a second analog signal on a second one of the plurality of A/D input lines, the microcomputer further including an A/D converter converting the first analog output signal into a first digital signal and converting the second analog signal into a second digital signal, the first one of the plurality of A/D input lines having a first measurement interval, the second one of the plurality of A/D input lines having a second measurement interval, the second measurement interval being outside of the first measurement interval,
wherein the first one of the plurality of A/D input lines is coupled to a first potential during the first measurement interval, and
wherein the second one of the plurality of A/D input lines is coupled to a second potential during the second measurement interval.
2. The electronic device according to claim 1, wherein the first one of the plurality of A/D input lines is further coupled to at least one digital port of the microcomputer.
3. The electronic device according to claim 2, wherein each of the at least one digital port provides a first resistance during the first measurement interval and provides a second resistance less than the first resistance when outside of the first measurement interval.
4. The electronic device according to claim 1, wherein the sensor output line is coupled to the first one of the plurality of A/D input lines via at least one voltage divider.
US08/793,285 1994-09-10 1995-08-17 Device for suppressing signal interference Expired - Fee Related US5773900A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4432229.1 1994-09-10
DE4432229A DE4432229C2 (en) 1994-09-10 1994-09-10 Electronic device
PCT/DE1995/001082 WO1996007872A1 (en) 1994-09-10 1995-08-17 Electronic device

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EP (1) EP0783664B1 (en)
JP (1) JP4021475B2 (en)
KR (1) KR100385029B1 (en)
DE (2) DE4432229C2 (en)
WO (1) WO1996007872A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5037129A (en) * 1989-04-06 1991-08-06 Robert Bosch Gmbh Safety device for vehicle occupants
US5062065A (en) * 1989-10-06 1991-10-29 Leopold Kostal Gmbh & Co., Kg Environmental sensing and ventilation control system with compensation for sensor characteristics

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3411115A1 (en) * 1984-03-26 1985-10-03 Siemens AG, 1000 Berlin und 8000 München Sensor combination
US4800513A (en) * 1986-08-01 1989-01-24 Motorola, Inc. Auto-calibrated sensor system
DE3826767A1 (en) * 1988-08-06 1990-02-08 Kostal Leopold Gmbh & Co Kg Sensor device
DE4439886A1 (en) * 1994-03-12 1995-09-14 Bosch Gmbh Robert Electronic device with an acceleration sensitive sensor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5037129A (en) * 1989-04-06 1991-08-06 Robert Bosch Gmbh Safety device for vehicle occupants
US5062065A (en) * 1989-10-06 1991-10-29 Leopold Kostal Gmbh & Co., Kg Environmental sensing and ventilation control system with compensation for sensor characteristics

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KR970705738A (en) 1997-10-09
DE4432229A1 (en) 1996-03-14
KR100385029B1 (en) 2003-08-14
DE4432229C2 (en) 2003-04-10
JP4021475B2 (en) 2007-12-12
WO1996007872A1 (en) 1996-03-14
DE59510716D1 (en) 2003-07-10
EP0783664B1 (en) 2003-06-04
JPH10505667A (en) 1998-06-02
EP0783664A1 (en) 1997-07-16

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